Enhanced Visual Processing in Perihand Space: Effects of Handedness

Marc Grosjean, Leibniz Research Centre for Working Environment and Human Factors, Dortmund, Germany

Abstract

There is a growing body of evidence that visual processing is
enhanced in perihand space. Some recent studies also showed that this enhancement
is limited to the space around the right hand, at least in right handers. One
explanation for these findings is that visual processing is facilitated at
locations where action is more likely to occur. To test this notion, we had left
and right handers perform a visual discrimination task under four hand-position
configurations: Left only, right only, both hands, or no hands near the visual
display. Results showed qualitatively different patterns for the two handedness
groups. Visual sensitivity (d’) was higher when only the left hand was near
the display for left handers, whereas right handers performed better in the
right- and both-hands conditions. These findings tend to confirm that visual
enhancement is tied to the dominant hand, which is preferentially used for most
manual actions.